One of the comparison methods for evaluating fishing gears efficiencies is based on Catch per Unit Effort (CPUE). In this study, we used three different types of traps for catching oriental river prawn (Macrobrachium nipponense). Capture efficiencies and catch rates of cylindrical pot, opera house trap, and Hokkaido pot were compared with each other during the investigation in Anzali Lagoon. The results indicated that there is a significant difference (P˂0/05) among the amounts of CPUE of cylindrical pot (0.24±0.12 gr), opera house trap (4.17±0.84 gr) and Hokkaido pot (1.58±0.41 gr). There was a significant difference between the results of length frequencies of captured prawns that was trapped by cylindrical pot and opera house trap (P<0.05). Hokkaido, cylindrical and opera house traps were not significantly different from each other for length frequencies. The results indicated that opera house trap was an appropriate fishing gear for catching oriental river prawn because it ha...

The alignment of opto-mechanical components in the optical setups affects the measurement accuracy. In this paper we descr ibe a low cost auto-alignment of star tracker components mounted on the satellite. In the presented optical setup, the components on the motorized optical mount will be auto aligned using image processing in Lab-view software. The accuracy of the measurement is related to the motorized optical mount. In this work, the accuracy of alignment in 3 directions is 0.01 degree and repeatable.